1. Field of the Invention
The present invention relates to an information processing apparatus for distributing images photographed with an image capture apparatus to terminals on a network.
2. Related Background Art
Live Video Communication System:
Techniques are known by which images photographed with a camera are distributed via communication infrastructures such as the internet, and techniques are also known by which camera settings and operations for photographing are instructed. Products applying these techniques are sold, such as a video distribution system WebView/Livescope by Canon Inc. There are other products of Canon Inc. such as live network camera servers VB101 and VB150 and a network camera VB-C10.
The video distribution system utilizing the above-described product can provide camera control such as pan, tilt, zoom and rear light correction as well as video distribution via a network. This system is provided with an access control function and can limit camera control and video distribution in accordance with an access privilege of each user.
This system can further limit an area to be photographed under camera control. For example, although a privileged user can use all zoom functions equipped to the camera, a general user is limited to be able to use only some of zoom functions (e.g., tele edge cannot be used to a full extent). Such limitation is applied also to a pan function and a tilt function. The live network camera servers VB101 and VB150 can distribute a plurality of source camera images via a network.
Encryption Techniques/Authentication Techniques:
A method is known by which data can be transmitted and received secretly or safely by using an encryption algorithm. Generally, encryption algorithms are classified into a symmetrical key scheme using same key information as an encryption key and a decryption key and an asymmetrical key scheme using different key information as an encryption key and a decryption key. The former scheme uses the Data Encryption Standard (DES), the Advanced Encryption Standard (AES), the Rivest's Cipher 4 (RC4) and the like. The latter scheme uses the Rivest Shamir Adleman (RSA) scheme and the like. By using an asymmetrical encryption scheme (public key encryption scheme), it is possible to confirm validity of an electronic signature added to document information.
Secure Communication Techniques:
There is technology called the Secure Socket Layer (SSL) as a protocol for providing safety of communications such as Web accesses by HTTP. This technology is mounted on a large amount of software typically browser software. SSL is positioned at an upper level of TCP/IP and at a lower level of an application protocol such as HTTP and FTP, and provides functions of server authentication, communication data encryption and client authentication (optional).
A scheme of providing safety of wireless communications is defined by WAP Forum. This scheme provides Wireless Transport Layer Security (WTLS) which is part of the Wireless Application Protocol (WAP). The scheme is designed on the basis of SSL and provides functions generally similar to those of SSL, such as data integrity, encryption and terminal authentication.
A Challenge-Handshake Authentication Protocol (CHAP) scheme defined as RFC1334 is known as a method of providing a communication authentication function. This scheme is mainly used by the Point-to-Point Protocol (PPP) defined as RFC1661.
A method of securing communication safety at an IP level is also defined in the Internet Protocol version 6 (IPv6). For example, there are the Authentication Header (AH) for packet authentication, the Encapsulating Security Payload (ESP) also for encryption and the like. This technology is not limited to IPv6, but there is similar technology for the Internet Protocol version 4 (IPv4). These technologies are adopted in many Virtual Private Networks (VPN) products. VPN is used as a substitute for a private line incurring a large cost.
Wide Angle Optical Camera Techniques:
Image capture apparatus are in use which utilize a wide angle optical system such as a fisheye lens and an omnidirectional mirror. Products of these image capture apparatus include a Sharp omnidirectional camera unit of Sharp Semiconductor Corporation and a PAL-mieru camera of Tateyama Machine Co. Ltd. Many additional values can be provided by adopting such image capture apparatus as a network camera or network camera server. Typically, image taken at various angles can be supplied to a plurality of users by applying an image conversion function and an image cut-out function to images (panorama images) photographed with a wide angle optical system. A wide angle combo camera is known which is used in combination with a camera (PTZ camera) capable of camera control such as pan, tilt and zoom. This camera can provide some users with high definition images under control of the PTZ camera, while general users are provided with images cut out from a panorama image.
Specifically, there is a technique capable of confirming easily a photographing range (Japanese Patent Application Laid-open No. H07-095547). There is also a technique capable of allowing many users to control cameras connected to a network, when necessary (Japanese Patent Application Laid-open No. H08-163422).
Camera control can be limited when offering services of video information of a network camera or camera server capable of camera control (pan, tilt and zoom, or camera exchange) on the Internet. For example, it is possible to set for general users a camera control area (prohibition area) limiting an area to be photographed under camera control, or a limited camera (prohibited camera). However, a manager or a privileged user can access the prohibition area or prohibited camera. It is therefore difficult to apply sufficient camera control limitation for general users accessing at the same time when the manager or the like accesses.
If general users are excluded when a manager or a privileged user accesses, usage convenience of video information services is degraded.
Application of secure communications to such a system does not progress currently because of mainly high cost.